Lichens are one of the most common fungi found in the garden, and will grow on almost any surface, including trees, garden furniture, and indeed lawns. Lawns which are neglected or suffer from poor growing conditions, insufficient drainage, too much shade, and often underfed; are the most susceptible. One of the most common lichens to affect the lawn is the Dog Lichen. The upper surface of each plate is brown or nearly black when moist, but when dry the surface fades to grey and curls upwards to reveal the creamy white underside. Like moss, unless action is taken to remedy the underlying causes, the problem will inevitably continue to return.
Dog Lichen (Peltigera canina) in a lawn
The correct remedial action is twofold; an application of a Dichlorophen-based herbicide in spring and autumn to kill the spores of the lichen, and mechanical treatments of hollow-tine aeration of the lawn (to improve drainage and allow moisture, air and nutrients to reach and develop the root structure of the turf) together with intensive moss control and scarification. The mechanical treatments will improve the growing conditions of the lawn, and make it increasingly difficult for both moss and lichen to return.